In the United States and many other countries, heart disease is a leading cause of death and disability. One particular kind of heart disease is atherosclerosis, which involves the degeneration of the walls and lumen of the arteries throughout the body. Scientific studies have demonstrated the thickening of an arterial wall and eventual encroachment of the tissue into the lumen as fatty material builds upon the vessel walls. The fatty material is known as “plaque.” As the plaque builds up and the lumen narrows, blood flow is restricted. If the artery narrows too much, or if a blood clot forms at an injured plaque site (lesion), flow is severely reduced, or cut off and consequently the muscle that it supports may be injured or die due to a lack of oxygen. Atherosclerosis can occur throughout the human body, but it is most life threatening when it involves the coronary arteries which supply oxygen to the heart. If blood flow to the heart is significantly reduced or cut off, a myocardial infarction or “heart attack” often occurs. If not treated in sufficient time, a heart attack often leads to death.
The medical profession relies upon a wide variety of tools to treat heart disease, ranging from drugs to open heart “bypass” surgery. Often, a lesion can be diagnosed and treated with minimal intervention through the use of catheter-based tools that are threaded into the coronary arteries via the femoral artery in the groin. For example, one treatment for lesions is a procedure known as percutaneous transluminal coronary angioplasty (PTCA) whereby a catheter with an expandable balloon at its tip is threaded into the lesion and inflated. The underlying lesion is re-shaped, and hopefully, the lumen diameter is increased to improve blood flow. Such techniques have traditionally relied on CT scans performed before surgery and angiograms during surgery to identify important anatomical features of the vasculature associated with the interventions. However, the information from a CT scan is often inaccurate at the time of surgery since the aneurysm is continually evolving over time.
Further, interventional procedures in the intracardiac space are continually developing. In that regard, structural heart procedures, including but not limited to valve replacement, valve repair, catheter ablation for arrhythmia, left atrial appendage (LAA) procedures, patent foramen ovale (PFO) procedures, and atrial septal defect procedures, also rely on imaging of the corresponding heart structures. Without accurate and detailed images of the associated structures, these interventional procedures in the intracardiac space become difficult, if not impossible, to perform successfully.
In recent years, techniques have been developed for obtaining detailed information about coronary and peripheral vessels as well as the intracardiac structures. For example, Intravascular Ultrasound (IVUS) and Intracardiac Echocardiography (ICE) techniques employ one or more very small transducers arranged towards the end of a catheter to provide electronically transduced echo signals to an external imaging system in order to produce a two or three-dimensional image of the lumen, the vessel tissue, and/or the tissue surrounding the vessel. Often these high quality images are generated in substantially real time. The images from these techniques allow a user to view the form and structure of a site rather then merely determining that blood is flowing.
In some instances, these devices rely on mechanical movement of an imaging transducer (e.g., an ultrasound transducer) in order to repeatedly sample a multi-dimensional space. In order to provide accurate information, effort is made to coordinate the transducer motion and the associated ultrasound acquisition. In that regard, the external imaging system often controls the movement of the transducer. For example, in some instances the displacement of the imaging transducer is directly correlated to the voltage or current waveform of a control signal generated by the external imaging system.
While the existing devices and methods have been generally adequate for their intended purposes, they have not been entirely satisfactory in all respects. The devices, systems, and associated methods of the present disclosure overcome one or more of the shortcomings of the prior art.